Any Advice on using fibreglass on steel???

[sphynx]

I've got a leaky ole roof on my barge - after many different attempts to seal the many steel plates that make up the roof - I've settled on using 600 gsm CSM with resin over the entire roof and over the edges.
I've keyed the old paint really well and have been advised to use G4 sealant and then apply the fibreglass before he sealant cures.

any other advise on using fibreglass over steel and how to make a proper job?

cheers.....

 

[Joe_Cole]

Test a bit on the paint before you do the whole job. The fibreglass may either not adhere to the paint or (more likely) lift the paint.

 

[ShipsWoofy]

I just do not see it working, if anything you will possibly create a void where the mat lifts off the steel and the steel rusts away merrily unseen.

If it was me, and I am guessing, tar / bitumen and canvas.

But I would seek advice much like you are, I have never had luck trying to get grp to adhere to anything metallic, it just don't work!

 

[chippie]

My worry would be that you are depending on the adhesion of the paint.
I think it would work if it becomes a structure in its own right (which is what it seems like from your description).

As suggested, a small test area is a good idea , and a dry run to make sure your method is practical. Chopped strand mat soaks up lots of resin so make sure you have enough. I am guessing you will be using polyester resin , this goes off quite quickly so a bit of practice, and a helper would be a good idea.

I have had success in getting epoxy to grip to freshly ground steel on my ute, but doubt whether epoxy is viable for use with CSM.

Good luck

 

[William_H]

GRP or similar is used very successfully on aluminium to repair reinforce cracks in arcraft structure. However... It is vital to clean the metal perfectly with no rust or even oil smear left on the surface and it is always epoxy that is used. No I think you will be dissapointed ultimately in your repair scheme. Having said that it will probably reduce the leaks dramatically but beware of rust under the glass. A thinner layer of glass will peel off fairly quickly while if the glass is made sufficiently thick the existing cabin will merely be a mold for the new F/G and will in effect support itself sufficiently that it will not peel off. That is an extreme case. I would recommend the tar and paint rather than F/G. regards olewill

 

[oldsaltoz]

G'day sphynx,

I saw a canal barge that had the roof covered in what looked like Linoleum [Lino],
the owner had cut it size and glued It to the roof, then glued on some PVC angle around the edge to seal it and provide a clean drip line.

I would imagine the tar on the back of the Lino would melt onto the steel on a hot day in the sun, providing a pretty good seal and saving a squids.

Might be worth looking into, the one I saw had dine it 3 years before I saw it and it looked in perfect condition, he [the owner] said he would paint with some sand added when it started to look shabby, but I think that will be some time yet.

Hope this helps.

Avagoodweekend......

 

[DepSol]

If it is Glass fibre on Stainless then you wil have to etch prime the stainless if you are using a sealant.

However if you use 3M UV4000 it has a built in etch primer to it.

 

[Joe]

Can't see it working in the long term
One other way would be to sheath the entire deck in new 18mm ply, Then epoxy resin it all using a single or twin layer of woven roving.
One potential problem is that you would need to make sure there was no give in the ply, As this may cause cracks between the sheets.
Some method of bolting it down to the deck would also be needed.
If you can do it this way then it will last a very long time.
Joe

 

[snowleopard]

I once built a tri using aluminium tudes for the cross members. the recommended method of getting a bond was to sand the surface of the metal while it was covered in wet resin (prevents the surface oxidizing). Then to wrap glass all the way round so it tightened as it cured.

Seems a bit OTT for a tin roof!

I have covered a flat roof (timber) with grp. The suppliers said 300 gsm but I thought one layer of csm was a bit mean so used 600. Carry the glass over the edges so it acts as a waterproof layer in its own right and doesn't rely on the bond.

 

[nedmin]

having had steel boats for 25 years,dont use ply.Wood and steel dont mix.Eventually the steel will rust under the wood and cause you endless problems.

 

[PBooth]

The problem will come from different rates of expansion cracking the bond between the fibreglass and steel. If you could first apply some type of flexible sealant to the prepared deck and then laminate onto that? This would allow slight movement without cracking.
Peter

 

[tcm]

i agree with four legged friend. Fibreglass isn't for sticking to something like steel with differential expansion and goo all over the place.

Modern building materials for sealing flat roofs are the way to go, rolls of self-adhesive bitumen a few mm thick. Much quicker and cheaper. Also, it'll work rather than not work.

 

[Shantyman]

My advice would be to bite the bullet and rip off the old roof plating.

You can then make a proper job by "re-roofing" with steel or wood, using the original beams if they are sound.

Anything less will be a bodge-up and you stand a good chance of not being happy with it.

Trouble with bodge-ups is they never last and you end up re-doing the lot at greater expense!

Cheers.

 

[Blueboatman]

Re: Any Advice on using fibreglass on steel?Yes.Dont waste the money!

As usual TCM is right on the money here....Buy a big 'ol tub of latex waterproof paint from your local builders merchant, apply with a throwaway roller and tray .You can actually build up several mm of thickness,span weeping welds etc...And then do what SHANTYMAN suggests when you have the time and good weather to cut off the existing roof and lay new ply /epoxy etc onto the existing roof beams..

 

[Avocet]

Polyester doesn't stick to steel in the long term. It has been used for years to "bodge" cars through MOT tests but it always peels off sooner or later. Can you get a welder and just weld patches on the holes in the steel roof? If you're just looking for a temporary repair, then sheathing the whole lot with GRP will work for a few years but ultimately, you'll end up having to peel it all off and start again.

 

[kds]

Don't !!
Ken

 

[ZuidWester]

Green roof solution

Agree with TCM, but use EDPM roofing rubber sheets glued to the roof.
Firestone sell it in the UK. They quarantee it for 25 years. When that's done plant sedum plants all over the roof and your boat with be insulated in winter, cooled in the summer and turn heads all year round (see Flordepot.co.uk).
PM me if you want more info on sourcing green roof materials.